//pin d7 to d13: + led columns 1 to 7 respectively //pin d2 to d6: to base of transistors controlling - rows of leds const int A = 13; //declare your columns as Capital alphabets and the pins controlling them. const int B = 12; const int C = 11; const int D = 10; const int E = 9; const int F = 8; const int G = 7; const int a = 2; //declare your rows as small alphabets and the pins controlling the bases of the transistors switching them on or off const int b = 3; const int c = 4; const int d = 5; const int e = 6; void setup() { pinMode(A, OUTPUT); //declare all your pins as outputs pinMode(B, OUTPUT); pinMode(C, OUTPUT); pinMode(D, OUTPUT); pinMode(E, OUTPUT); pinMode(F, OUTPUT); pinMode(G, OUTPUT); pinMode(a, OUTPUT); pinMode(b, OUTPUT); pinMode(c, OUTPUT); pinMode(d, OUTPUT); pinMode(e, OUTPUT); } void loop() { int wait = 50; digitalWrite(a,HIGH); digitalWrite(A,HIGH); digitalWrite(E,HIGH); digitalWrite(F,HIGH); digitalWrite(G,HIGH); delay(wait); digitalWrite(a,LOW); digitalWrite(E,LOW); digitalWrite(G,LOW); digitalWrite(b,HIGH); delay(wait); digitalWrite(b,LOW); digitalWrite(c,HIGH); delay(wait); digitalWrite(c,LOW); digitalWrite(d,HIGH); delay(wait); digitalWrite(d,LOW); digitalWrite(e,HIGH); digitalWrite(E,HIGH); digitalWrite(G,HIGH); digitalWrite(B,HIGH); digitalWrite(C,HIGH); delay(wait); digitalWrite(e,LOW); digitalWrite(E,LOW); digitalWrite(G,LOW); digitalWrite(B,LOW); digitalWrite(C,LOW); digitalWrite(A,LOW); digitalWrite(F,LOW); }